SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4deaa7583841fbd7eafdb87674a8c12367820757a8bdeb664c73a5221a11141f' 
  AND token = '8EQw0aeUJny2V0jsRZmKxFXcejAxjYb+PDt0kWo01lA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}